> ## Documentation Index
> Fetch the complete documentation index at: https://docs.dualentry.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Introduction to the DualEntry Public API: a RESTful, JSON-based, server-to-server interface for reading and writing your organization's accounting data.

The DualEntry Public API provides programmatic access to your organization's accounting data. It's designed for server-to-server integrations using RESTful conventions and JSON format.

## Overview

* **RESTful API**: Standard HTTP methods (GET, POST, PUT, DELETE)
* **JSON Format**: All requests and responses use JSON
* **Secure**: API key-based authentication
* **Versioned**: Both V1 and V2 available; V2 is recommended for new integrations

## What you can build

Build integrations to automate accounting workflows, sync data with external systems, and create custom financial applications.

<Info>
  **Common Use Cases**: Automated invoicing, data synchronization with CRM/ERP systems, custom reporting, third-party integrations with payment processors or e-commerce platforms.
</Info>

## Versioning

The API supports two versions:

* **V2** (`/public/v2/`) -- Recommended for new integrations. Adds depreciation-books, intercompany-journal-entries, and enhanced fixed-assets with multi-book depreciation.
* **V1** (`/public/v1/`) -- Maintained for backward compatibility. Existing integrations continue to work without changes.

See the [Changelog](./api-changelog) for migration details.

## API resources

The API provides access to:

* **Setup**: Accounts, Items, Classifications
* **Master Data**: Companies, Customers, Vendors
* **Transactions**: Invoices, Bills, Journal Entries, Payments, Purchase Orders
* **Automation**: Recurring Transactions, Attachments
* **V2-only**: Depreciation Books, Intercompany Journal Entries

## Getting started

1. Get an API key from your DualEntry administrator
2. Include the API key in the `X-API-KEY` header with every request
3. All endpoints require authentication and are rate-limited

<Warning>
  **Base URLs**:

  * Production: `https://api.dualentry.com`
  * Development: `https://api-dev.dualentry.com`
</Warning>

***

**Next:** [Learn about Authentication →](./authentication)